DIY Breathalyzer may be the hit of the party

Okay, this may not be saving any lives, but it makes for a fun novelty at your next rager. Most Breathalyzers aim to keep you from driving when you’ve had too many. The Squidalyzer encourages party-goers to drink more and more by treating a high blood-alcohol-content with great fanfare. An Arduino, a gas sensor, and Processing all come together for this hack. A television interface tells you when to blow into a cup which houses the sensor, and gives a reading of what it measures. Blow higher than the last guy and you’ll break the record. Watch the demo after the break to see the fun [Geoff] had with it. And remember, friends don’t let friends solder drunk.

BAC = Blood alcohol concentration. This is somewhat accurately determined by the alcohol content of the breath you exhale. Obviously having alcoholic substances in your mouth at the time of reading will screw it up big time.

I often thought building something like this could be quite useful — or quite dangerous, both of which have been pointed out.

On the tech side, it does seem calibrating it would be the trick. Maybe a score 100 means 0.10%? Nah, too easy. But even if… even the units used by police here have problems with calibration and need regular checking and recalibrating.

But if it could be done maybe responsible hosts or bar owners could legally hold somebody’s car keys until they fell to the legal limit.

On an editorial note:
Wow, 0.02% in Sweden and 0.05% in Australia (stereotyped home of big Fosters cans & “Croc Dundee”-style drinkers)… hard to believe many Americans complain about being in an over-regulated nanny state with most places allowing from 0.08 to 0.10% as the limit! The US can legally drive drunker than others.